Friday, May 31, 2013

Focus Stacking a Daffodil

One spring afternoon, with nothing much better to do, I decided to go and pull up some unsuspecting daffodils from the garden, to use in a diabolical experiment.Once I had procured the hapless flowers, I picked out the finest example, cruelly tossing away the outcasts and leaving them to make their own way in this pitiless world of ours. And then set up the terrified champion on a table, with my looming lens just millimetres away from its quivering bloom.I wanted to try my hand at a bit of focus stacking. Often when getting close to an object, even with a dedicated macro lens, the depth of field, or, more importantly, the lack of it can make getting a sharp image from front to back a real challenge, ranging from impossible, all the way to unattainable.So, you would assume that my dream of getting a sharp macro image of this flower was looking unlikely. And when you consider I don’t even own a macro lens to begin with, you could be mistaken for thinking that this idea was nothing but the hysterical imaginings of a demented buffoon. But, let me put your mind at ease if I may. Truly I do not own a macro lens, but I do own a set of adaptor rings that can be fitted to my existing lenses, and once these beauties are locked in place, they render any lens capable of macro capabilities.

The downside of these rings, and the resulting need for focus stacking is that, although useful, they are rather cheap, being just plastic rings that fit between the lens and the camera. So the upshot is, they cut off all electronic communication between the said lens and camera, which of course removes any auto focusing and depth of field capacity. Meaning my actual depth of field was as close to zero as you can really get.

Once the camera was set up on its tripod and fixed firmly in place, which was obviously a necessity, as the camera and the flower needed to stay as still as possible for the entire process, I was ready to begin the operation.I used all three rings together to maximise the macro properties, and fitted them between the camera and a 24-105 lens, its front element stationed about 10mm away from the front aperture of the daffodil. It was so close in fact I had to make sure I didn’t knock the flower when adjusting the camera.As autofocus was no longer available I used the Live View function of the Canon to make sure my manual focusing was as spot on as could be for each shot. I began by taking a shot of the part of the flower nearest the lens, then carefully refocusing further and further, onto the stigma, then down the stile, and into the bowels of the blossom pit itself.

In Live View the focusing point can be moved around the screen, and you can also zoom in to really makethose fine focusing adjustments

I’m pretty sure ‘stigma’ and ‘style’ are correct floricultural expressions, but I’m a bit shaky on whether ‘bowels of the blossom pit’ is entirely acceptable. Nevertheless, deep into the floral cavity I roamed until my focusing had reached as far as it could go.

Here is an animated GIF produced from the shots I got, showing how the focusing journeyed into the daffodil.If it isn't playing then just click on the image and it may do the trick.

So once the shots were got, they were then dutifully loaded on the computer and opened up in Adobe Bridge, as is my preference, but they could also be opened in any of your favourite image editing programmes of course. Well, probably not all of them but most of them, I would imagine. Once that was done, I opened up the first image in Camera Raw and carried out some basic tone and contrast adjustments to give the image a bit more punch, nothing too fancy mind, just enough to lift it a bit, that’s all we’re looking for, so don’t go overboard, I really won’t tell you again.Clicking done, and back in Bridge I applied those setting to the rest of the images. Next I went to Tools – Photoshop – Photomerge, with the open images automatically brought in from Bridge, I made sure that ‘Blend Images Together’ was unchecked, we do not want Photoshop interfering at this point anymore that it needs to. I know it means well, but a line has to drawn somewhere.

Bringing in the images from Bridge to Photoshop via the Photomerge command

The Photomerge dialogue box, with Layout selected as Autoand the Blend Images Together unchecked

Hitting the OK button and letting it do what it does best, the next thing I knew I was in Photoshop and all those images were in layers of the same file, and had been aligned as well as they could be. Because a tripod was used when taking the photos, resulting in only small variations on positioning, the powerful align tool should now have them spot on.Next up it was time to let Photoshop unleash one of its other magnificent devices, namely its Auto Blend Function. So selecting all the layers and going to EDIT – AUTO BLEND LAYERS, I made sure that Stack Images was selected, and the OK button was duly activated.

Through some clever mathmatics Photoshop managesto find the sharpest parts of each layer and blendwith the other layers.

Now that I had all the layers blended together through the use of masks, if the outcome didn’t look quite how it should be, the masks could be used to bring back or hide parts of the each image. This can be a bit tricky as it’s not always possible to see directly which area of the image is on which layer, but a little bit of trial and error should get the results.

The Photoshop layers with masks applied

Finally, after adding some levels/curves and a bit of sharpening, before I knew it a focus stacked image was there before my very eyes.

While it's not what you would call an outstanding example of the genre, the technique has made possible something I could never have achieved otherwise.

So thanks to the very useful tools that Photoshop has to offer, it’s relatively easy to get an image with a depth of field that would be impossible to achieve in camera. And while the dictum of trying to get everything right at the time of shooting is a noble one, there are times when it just isn't possible, which is where post processing can be as useful in the procedure as the camera itself.